There is a trend toward less invasive surgical procedures performed by introducing small diameter, flexible tools into natural body openings and small incisions. These tools can enable tissue visualization, imaging, analysis, manipulation, cutting, coagulation, and removal. An example of a procedure done through a natural body opening is polyp visualization and removal during a colonoscopy. Examples of procedures done through one or more small incisions include laparoscopic hysterectomy or cholecystectomy. Laparoscopic incisions are typically 3 mm to 15 mm in diameter. Some procedures can be done through incisions 3 mm or smaller, and have been called “needlescopic”. One type of laparoscopic surgery is single incision laparoscopic surgery, where a multiport trocar is used to introduce a cluster of surgical tools. Incisions that start from an instrument already in a natural body opening, called natural orifice translumenal endoscopic surgery (“NOTES”), are a topic of current surgical research, as are various percutaneous procedures. Examples include NOTES cholecystectomy.
A small-diameter, flexible tool can be beneficial for such procedures. To access regions that are not necessarily close to the point of tool introduction, longer tools may also be desirable.
Long, thin, flexible waveguides for optical radiation are well adapted for performing the procedures described above, and suit the current growing interest in and use of laser surgery. For example, solid core silica fibers are used to guide wavelength of KPT (532 nm), Nd:YAG (1.06 μm), Ho:YAG (2.1 μm) and Tm:YAG (2 μm) lasers widely used in medical applications. For CO2 laser beams (approximately 10.6 μm wavelength), hollow waveguides may be useful, as the CO2 wavelength is generally highly absorbed in materials traditionally used for optical fibers, such as silicates and thermoplastic polymers. Hollow waveguides may be made of metal, such as disclosed in U.S. Pat. Nos. 4,652,083 and 4,688,893, or metalized tubes such as disclosed in U.S. Pat. Nos. 5,440,664; 5,567,471; and 7,315,675 to Harrington et al., in which a metal mirror guides the optical radiation.
Flexible hollow waveguides are manufactured in some techniques by drawing structured thermoplastic preforms. Examples of such a structure are described by Fink et al. in U.S. Pat. Nos. 6,463,200 and 7,311,962 in which a dielectric stack of materials having different refractive indices is arranged in concentric cylinders about the waveguide axis thus providing the mirror structure that guides the radiation. Flexible hollow waveguides drawn from structured thermoplastic preforms are also disclosed in U.S. Pat. No. 7,272,285 to Benoit et al. and U.S. Pat. No. 7,295,734 to Bayindir et al., as well as in the following U.S. Patents assigned to OmniGuide, Inc.: U.S. Pat. No. 6,788,864 by Ahmad et al.; U.S. Pat. No. 6,801,698 by King et al.; U.S. Pat. No. 6,898,359 by Soljacic et al.; and U.S. Pat. No. 7,142,756 by Anderson et al.
Generally, waveguides may be strengthened and protected by additional elements on the outside, such as jackets, and may have additional elements that add functionality, such as distal tips. Waveguides disposed inside protective jackets and having additional functionality elements are often referred to as waveguide assemblies.
For further mechanical strength and manipulation, it is often desirable to place waveguides or waveguide assemblies inside other mechanical structures, known as waveguide conduits, which may provide protection, strength, and structure for surgical access control. Waveguide conduits are typically placed on or over waveguides or waveguide assemblies after manufacturing or assembly of the waveguides, generally at point of use. Waveguide conduits can be either flexible or rigid, or have a rigid portion and a flexible portion. A waveguide conduit can have multiple functions. A primary and important function of the waveguide conduits is to give a user control of surgical access, in either a hand-held manner, known as handpiece-style waveguide conduits, or by means of electromechanical actuators or robotic devices such as Flexguide™ products available from OmniGuide, Inc., based in Cambridge, Mass.
Examples of known robotic surgical systems utilizing lasers and other instruments are provided by Mohr in U.S. Patent Publication No. 2009/0171372, by Williams et al. in U.S. Patent Publication No. 2009/0248041 and by Prisco et al. in U.S. Patent Publication No. 2010/0249507, for example, all assigned to Intuitive Surgical Operations, Inc. and/or Intuitive Surgical, Inc. of Sunnyvale, Calif., which provides the Da Vinci™ robotic platform. Robotically assisted surgery through a single port utilizing an image capturing device and multiple surgical tools is described by Mohr in U.S. Pat. No. 8,517,933.
Other functional elements may include mechanical protection of the waveguide, control of waveguide bending for surgical access and control of associated optical performance variation (optical loss due to bends) of the waveguide, means for keeping the waveguide inside the waveguide conduit and optically aligned with the conduit distal tips during usage, couplers for mechanical coupling of the waveguide conduit with an external manipulator, and mechanical supports of other functional elements that may be affixed to the conduit (e.g., distal tips, suction and/or irrigation tools, etc.). The waveguide conduit is preferably steerable in a well-controlled and precise motion manner, critical for minimally invasive surgical procedures, by means of a handle and/or attachment to a manipulator. It is preferably sterilizable and may be disposable or reusable.
Suitable materials for the waveguide conduit portions include stainless steel (e.g., 300 and 400 series surgical grade steels), titanium, aluminum, various alloys of aluminum, ceramic materials such as alumina and zirconia, and polymer materials such as silicones, polyamides, polycarbonates, PEEK, and polyolefin.
The configuration of the waveguide conduit depends on the particular application. It may vary in length and may contain several bends placed anywhere between distal (adjacent to the surgical site) and proximal ends (closer to the surgeon or other user of the device), depending on the requirements of a particular application. For example, conduits used for oral surgeries (e.g., base of tongue), are generally rigid and relatively short with fewer bends than waveguide conduits used for laryngeal work. A typical range of bend angles between distal and proximal ends is 20°-60° and total length may be from about 5 cm to about 25 cm for oral surgeries, while for laryngeal surgical procedures the bend angles maybe larger, up to 90°, and the total length may be up to about 45 cm. Yet for laparoscopic procedures, even longer waveguide conduits are utilized, up to about 65 cm.
Giving a surgeon precise control of waveguide position and direction of firing laser radiation is important. Therefore, waveguide conduits for handheld usage generally have handles designed for a comfortable grip, for example, as in OmniGuide ENT handpieces, sold in ENT handpiece sets, catalog number ENT-HS. However, the longer waveguide conduits can present an issue with tremor from a user's hand or other source of vibration being amplified at the distal end. In addition, over longer periods of use in a hand-held manner, hand and finger fatigue may develop and result in decreasing ability for precision manipulation and aiming due to surgeon hand fatigue.
Some approaches to fix waveguides in place are known to those skilled in the art. For example, one prior art laser radiation delivery structure 10, FIG. 1, releasably secures a single-use waveguide 12 inserted through a reusable rigid waveguide conduit 14, also referred to as a handpiece 14, of the delivery structure 10. An elastic compression gripper 16 and a threaded cap 18 are included in the proximal portion of the handpiece 14. When the cap 18 is rotated, it acts on the gripper 16 and compresses it onto the waveguide 12 when rotated in a first angular direction and allows the gripper 16 to relax and release the waveguide 12 when rotated in the opposite angular direction. This method to keep waveguides in place is used, for example, in OmniGuide handpieces, sold in handpiece sets, catalog number ENT-HS. While using a soft elastic gripper may reduce potential for mechanical degradation of the waveguide, a disadvantage of such a method may be variable control of the gripping force and compression exerted on the waveguide, due to variation in the gripper material properties and gripper dimensions, which can be challenging to control to tight tolerances due to the elastic nature of the material. Also, the gripper may wear over time and variability in the waveguide diameter and the user action of tightening the cap can affect the reliability of the grip on the waveguide.
It is desirable to have a waveguide conduit which enables a surgeon to exercise precise control and aiming of laser radiation delivered via a waveguide with minimal amount of tremor and minimal hand fatigue over time.
It is desirable to reliably keep a waveguide in a waveguide conduit and to hold a waveguide properly during use and manipulation, thus avoiding excessive protrusion or recess of the waveguide distal end relative to a distal tip of the waveguide conduit, as well as minimizing uncontrolled changes in the waveguide position.